Australian Services Union says Jetstar check-in staff will take industrial action this Friday by refusing to charge excess baggage for travellers.

The union says "No Weigh Day" is the first industrial action ever taken against the airline.

Airports in Sydney, Melbourne, Cairns, Brisbane and the Gold Coast will be affected.

Workers say they are frustrated with stalled negotiations over a new workplace agreement which have been going on for more than a year.

But union representative Linda White says travellers will not face any delays.

"It's not going to disadvantage travellers at all, in fact it's a bonus for travellers," she said.

"(Those) who will often pay excess baggage will have that waived by our members at the front line.

"We will be weighing their bags but will not be charging them if they're over weight."

Ms White says Jetstar makes about AU$50,000 a day in excess baggage charges.

"They won't be happy but let's be clear, it's about time they valued the work of their frontline customer service staff," she said.

"This is action we'd rather not take but we have to because we don't think they're responding to our reasonable claims."

Jetstar says it is disappointed by the union's decision to take industrial action.

It says it has been negotiating in good faith with the union over the past 12 months to finalise an agreement covering around 400 employees across seven of its Australia ports.